The Sentry comes with a Type-K unless you specify a Type-S when you order your kiln. If you install a Type-S on your Sentry controller, please make sure that you change the thermocouple type under Options. Otherwise your kiln could over-fire.

Paragon controllers have all used the Type-K thermocouple. The Sentry controller, made by Orton Ceramic Foundation, was the first Paragon controller that could also accept the Type-S thermocouple. The DTC 100, 600, 800 and 1000 series use Type-K only.